There is a frame house insulated with mineral wool in the outer walls. The question of what to fill the interior walls?
Mineral wool for insulation makes no sense. In terms of interior sound insulation makes sense. But exterior walls are insulated with a vapor barrier on the inside and a vapor-permeable film on the outside, so that moisture escapes outside.
But in the inner walls of the moisture will have nowhere to go if there will be mineral wool. I'm afraid it will accumulate there.
What do you use to fill the interior walls in a frame house?
There is no temperature difference, how can it accumulate moisture? Only if you pour it from a kettle.
You can use mineral wool or soundproofing boards, windproofing against dust on both sides, and that's it.
There is always moisture in the air (atmospheric). But it is insignificant and nothing terrible for the insulation.
Partitions in a frame house also need not be framed (with filling) – can be without it, and purely wooden, covered with linings or plastered.
You can also try to fill them with expanded clay or hollofiber. They will both get wet and dry.
The primary task of partitions is soundproofing. Many manufacturers have products specially designed for this purpose.
Moisture will not accumulate inside the mineral wool, as the temperature difference between rooms is almost imperceptible. The difference in partial pressures inside the rooms is insignificant, unlike in enclosures where special attention must be paid to non accumulation of moisture inside the structure in view of the large temperature differences outside and inside.
The construction can be constructed as follows: Wooden or metal frame, plasterboard at least 9mm, then mineral wool, the thickness you choose depending on the thickness of the partition you can afford, based on the area of space, then again plasterboard.
Be sure not to forget to lay the joints of the partition to the walls and ceiling with noise insulation tape to prevent the transfer of noise in those areas.